Tuning-transformer for wireless systems.



APPLICAflOIl min DEC. l5. ma.

Patented Apr. 6, 1915.

2 SHEETS-SHEET 1.

R 0 w M m 4r w. J Z W W 0 I a M w W m a m P N V W A TTOR/VEYS R. R. GOLDTHORP.

TUNING TRANSFORMER FOR WIRELESS SYSTEMS.

APPLICATION FILED own. 1913.

1 134 840. Patented Apr. 6. 1915.

2 SHBBTSBHEET 2.

MAXIMUM INDUGTAN CE WITNESSES INVENTOR ATTORNEYS 12050012, Gout/ear I fine and shar ROBERT E. GOLDT HOBP, OF HARTFORD, CONNECTICUT.

TUNING-TRANSFORMER FOR WIRELESS SYSTEMS.

Specification of Letters Patent.

Patented Apr. 6, 1915.

Application filed December 15, 1913. Serial No. 806,776.

To all whom it may concern:

Be it known that I, RoBER'r R. Gonn- THORP, a citizen of the United States, and a resident of Hartford, in the county of- Hartford and State of Connecticut, have invented a new and Improved Tuning-Transformer for Wireless Systems, of which the following is a full, clear, and exact description. v

This invention relates to a tuning transformer for wireless systems and relates more particularly to a transformer of that type having relatively movable primary and secondary coils in connection with means for varying the effective lengths of the coils to obtain a wide range of tuning capacity.

The invention has for its general objects to improve and simplify the construction and operation of transformers of the character referred to so as to be reliable and eflicient in use, composed of comparatively few parts, inexpensive to manufacture and keep in operative condition, and capable of quick, easy and accurate adjustment.

Another object of the invention is the provision of a transformer having a novel arrangement of inductively related coils of simple and novel design, whereby -extremely tuning is rendered possible,

such coils belng wound fiat and elongated.

and pivoted co-axially together in the closest proximity possible, whereby tuning. can be efiected by shifting the movable coil through an arc of ninety degrees, from one extreme to the other, which adjustment, to-

ether with the changing of the effective fingths of the respective coils, gives an extremely wide range of tuning.

Another object of the invention is that extreme close coupling between primary and secondary is obtained; therefore less loss of energy in the secondary.

Still another object is to so mount the movable coil that in addition to its angular adjustment with respect to the other coil, it can be moved bodily to and from the relatively fixed coil for the purpose of increasing the tuning range. i

With such objects in view, and others which will appear as the description proceeds, the invention comprises various novel features of construction and arrangement of 1 parts'such as will be set forth with particularity in the .following description and claims appended hereto. x

-In the accompanying drawings, which on which the wire is illustrate certain embodiments of the invention, and wherein similar characters of reference indicate corresponding parts in all the views, Figure 1 is a view of the transformer as seen from underneath, as when the bottom plate of the casing is removed; Fig. 2 is a sectional view on the line 2-2, Fig. 1; Fig. 3 is a plan view of one of the windings or coils of the transformer; Fig. 4: is a plan view of the adjusting knobs for the movable coil and the switches; Fig. 5 is a diagrammatic windings; and Fig. 6 is a perspective View of a modified form of transformer, wherein the movable coil has both rotative and axial movement. I v I Referring to the drawing, A designates the casing that incloses the transformer and which consists of a back or bottom plate 1 and a chambered .body or cover 2, such cas ing being made of some suitable insulating material. Rotatably mounted -within the casing is an approximately elliptical plate or support B of insulating material which has one surface disposed adjacent to the inner surface of the cover 2 of the casing, and the juxtaposed faces have the coils or windings of the transformer, the primary coil p being fastened to the plate or carrier B and the secondary coil being fastened to g primary to thesecondary coil for varyin the inductive effect. The axle is journale within a sleeve or tubular bearing 7 which extends out of the casing through an open in 8 in the center of the cover 2.

he windings or 00115 are mechanically view of the transformer the same, except that of course the primary windin is made of wire of coarser gage than t e secondary winding. Each winding or coil is absolutely flat and is approximately elliptical or elongated. A.-

cardboard or other plate 10 forms a base secured. This plate 10 is mounted in a suitable coil-forming device, and the surface of the plate is shellacked. The wire is then wound into a coil and adheres to the plate by means of the shellac or equivalent material, and after the coil is completely formed the whole winding may be again shellaced. Loops or taps 11 are provided at various points in the coil so as to divide the latter into a plurality of sections whereby more or less of the coilcan be connected in circuit by a multi-point switch. The coils when comleted are secured in place by the back suraces of the plates 10 being glued or otherwise fastened to the carrier B and cover 2. The primary winding p has its loops or taps connected with contact points 12 which are arranged on the side of the carrier B opposite from that which has the winding, and a movable contact or spring 13 is adapted to engage the contact points '12 so as to connect more or less of the primary winding in circuit. The movable contact 13 is fastened to a spindle or rod 14 which passes through the axle and has one end journaled in the bushing 5 and the other end journaled in the bushing 15 in the outer end of the axle, there being a knob 16 fastened tov the outer end of the spindle so as to turn the same, the spindle 14 being rotatable with the axle when the knob ,6 is turned for the purpose of changing the position of the primary winding. In order to connect the primary winding, which is movable, with the outside circuit, a split ring or annular contact 17 is fastened to the carrier B in concentric relation to the axis of rotation, and the terminal 18 of the primary wind- I ing is connected with this ring, while the various sections of the winding are connected with the respective contact points 12. Bearing on the ring is a spring contact 18 which 18 fastened to the back plate 1 and is connected by a wire 19 with the primary binding post 20 on the cover of the casing. The other primary binding post 21 is connected by a wire 22 with a contact 23 fastened to the back 1 in such a position that its free end constantl bears on. the spindle 14, which serves to e ectrically connect the switch contact 13 with the contact 23.

The secondary winding has its loops or taps connected with contact points 24 which are arranged on the outside of the cover 2 in an are around the center thereof and ar ranged to engage these contact points is a spring contact 25 which is fastened to a knob 26 rotatable on the tubular bearing 7. A metallic spring washer 27 is in electrical engagement with the hub of the contact 25 and also in engagement with a metal plate or washer 29, which bears on the cover 2- and is electrically connected by a wire 30 with the secondary binding post 31. The other binding post 32 is connected by a wire 33 with one terminal of the secondary winding s, while the other terminal in this windto obtain an angular adjustment of the coils, but this post also enables the secondary eleright-angles to. eachother.

connected withthe last contact point 'are spaced apart by a collar 34 which is fastened to the tubular bearing 7. On the cover is an indicating device or mark 35 with which cotiperates a finger 36 on the knob 6, the finger being so arranged that when the same is opposite the indicating device -35, the primary and secondary windings will be positioned with their major axes parallel, which produces maximum inductance. The knob 6 can be turned to the right or left in order to throw the major axes of the coils out of Farallelism, whereby the'straight portions 0 one coil will intersect the straight ortions of the other coil and change the lnductive effect, it being understood that the minimum inductance is obtained when the major axes of the coils are at right-angles to each other. For facilitating the adjustment of the primary coil as regards its effective length, the outer surface of the knob 6 is provided with a scale '37 over which projects an index finger 38 on the knob 16, and by the position of this finger with respect to the divisions of the scale it is possible to ascertain'how many sections of the rimary coil are in circuit.

In the modi cation shown in Fig. 6, the primary and secondary elements are designated P and S, the coils thereof being the same as in the construction previously described. The secondary element S is rotatably mounted on an axle or post 40 so as ment S to be adjusted axially away from or toward the primary element,it being understood that the transformer is so mounted on a support that the post 40 will be horizontal, so that the secondary element will remain in any position of adjustment toward or from the primary element.

From the foregoing description taken in connection with the accompanying drawings, the advantages of the construction and method of operation will be readily understood by those skilled in the art to which the invention appertains, and while I have described the principle of operation, together with the devicewhich I nowconsider to be the best embodiment thereof, I desire to have it understood that the device shown is merely illustrative, and that such changes may be made when'desired as are within the 1 scope of the appended claims.

Having thus described my invention, I claim as new and desire to secure by Letters Patent; I

1. A tuning transformer comprising fiat, 5 elongated primary and secondary windings arranged co-axially and relatively adjustable-from a position with the major axes parallel to a position with the said axes at 2. A tuning transformer comprising flat, elongated primary and secondary windings arr-an ed co-axially and relatively adjustable". Tom a position with the major axes parallel to a position with the said axes at right-angles to each other", and-means for permitting movement of the coils toward and from each other. a

3. A tuning transformer comprising two flat, elongated parallel primary and secondary coils pivotally connected for rotation through an arc of ninety degrees, and means for varying the effective length of each coil. I

4. A tuning transformer comprising two flat, elongated parallel primary and second ary coils pivotally connected for rotation through 'an arc of ninety degrees, and a multiple-point contact switch for changing the effective length of each coil.

5. A tuning transformer comprising a stationary coil, a movable coil, a tubular axle connected with the movable coil,said

coils being fiat and parallel and elongated,

means for turning the axle to change the position of the coils, contact points connected with the movable coil for dividingthe same into sections, a movable contact for engaging the contact points, a spindle journaled in the axle and connected with the movable contact for moving the same, means .two' subscribing witnesses.

for turning the axle to change the position of the coils, contact points connected with the movable coil for dividing the same intosectlons, a movable contact for engaging the contact points, a spindle journaled in the axle and connected with themovable contact for movingthe same, meansfor connecting through the said contact and contact points the movable winding with a circuit, a slip ring contact connection for connecting the movable winding in circuit, contact points connected with the fixed'winding, and a.

movable contact rotatable about the axes for engaging the last-mentioned contacts.

In testimony whereof I have signed my name to this specification in the presence of ROBERT R. GOLDTHORP.

I Witnesses:

TIMoTHY J} DELANEY, HENRY S. BRowN. 

